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Separation membrane and method for producing the same

a separation membrane and membrane technology, applied in the field of separation membranes, can solve the problems of reducing permeability, difficulty in meeting high permeability, and void ratio inside the membrane becomes lower, and achieves excellent chemical and physical strength, high pure water permeability, and high virus removal performance.

Active Publication Date: 2015-11-03
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a separation membrane that has high virus removal performance, high pure water permeability, and high chemical and physical strength. This is achieved by using a high concentration of a polyvinylidene fluoride-type resin with excellent physical strength in a three-dimensional network structure. Additionally, a support layer is used to bear high physical strength and ensure the durability of the membrane. This membrane can be used in a water treatment process, where it is necessary to remove trace components such as viruses.

Problems solved by technology

However, it was very difficult to also satisfy high permeability.
Although physical strength is improved by using the high-concentration resin stock solution, a void ratio inside the membrane becomes lower and thus permeability decreases.
In order to increase the permeability, it becomes necessary to decrease the thickness of the membrane, resulting in a decrease in a physical strength.
Also, abrasion and damage of the surface are caused by suspended solids in a solution to be separated and thus contaminants such as viruses are leaked.
Furthermore, when the thickness of the film is decreased, the membrane may not sometimes exhibit a virus removal performance as the original purpose.

Method used

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  • Separation membrane and method for producing the same
  • Separation membrane and method for producing the same

Examples

Experimental program
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Effect test

example 1

[0109]A vinylidene fluoride homopolymer having a weight average molecular weight of 417,000 (38% by weight) and 62% by weight of γ-butyrolactone were dissolved at 160° C. This polymer solution and an aqueous 85% by weight γ-butyrolactone solution were simultaneously ejected through an outer tube of a double co-extrusion head and an inner tube of the double co-extrusion head, respectively, and then the solutions were solidified in a bath of an aqueous 85% by weight γ-butyrolactone solution at a temperature of 10° C. The obtained membrane was stretched in water at 90° C. by 1.5 times. The obtained membrane is a hollow fiber membrane having a spherical structure and this membrane was used as a support.

[0110]Next, 9.6% by weight of a polyvinylidene fluoride homopolymer having a melt viscosity of 6,400 Pa·s (Kynar® HSV900, manufactured by Arkema Inc.) and 2.4% by weight of a polyvinylidene fluoride homopolymer having a melt viscosity of 3,200 Pa·s (Kynar® 760, manufactured by Arkema Inc....

example 2

[0111]A polyvinylidene fluoride homopolymer having a melt viscosity of 6,400 Pa·s (Kynar® HSV900, manufactured by Arkema Inc.) (12% by weight) was dissolved in N-methyl-2-pyrrolidone to obtain a membrane-forming stock solution for a separation-functional layer. This membrane-forming stock solution was uniformly coated on the surface of the hollow fiber membrane obtained in Example 1 and then solidified in water at 23° C. to produce a hollow fiber-shaped separation membrane bearing a separation-functional layer having a three-dimensional network structure formed on a support layer having a spherical structure. The membrane structure and membrane performance of the obtained separation membrane are shown in Table 1.

example 3

[0112]A polyvinylidene fluoride homopolymer having a melt viscosity of 6,400 Pa·s (Kynar® HSV900, manufactured by Arkema Inc.) (9.6% by weight) and 2.4% by weight of a maleic anhydride-modified polyvinylidene fluoride homopolymer “manufactured by Arkema Inc., Kynar® ADX-111” were dissolved in N-methyl-2-pyrrolidone to obtain a membrane-forming stock solution for a separation-functional layer. This membrane-forming stock solution was uniformly coated on the surface of the hollow fiber membrane obtained in Example 1 and then solidified in water at 23° C. to produce a hollow fiber-shaped separation membrane bearing a separation-functional layer having a three-dimensional network structure formed on a support layer having a spherical structure. The membrane structure and membrane performance of the obtained separation membrane are shown in Table 1.

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Abstract

A separation membrane including a separation-functional layer is provided, wherein the separation-functional layer contains a polyvinylidene fluoride-type resin having a melt viscosity of 3,300 Pa·s or more, and also the separation-functional layer has a three-dimensional network structure. A separation membrane is provided having high virus removal performance, high pure water permeability, and high physical durability and high chemical strength, which can also be used in the field of water treatment.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is the U.S. National Phase application of PCT International Application No. PCT / JP2009 / 066331, filed Sep. 18, 2009, and claims priority of Japanese Patent Application Nos. 2008-240733, filed Sep. 19, 2008 and 2009-085775, filed Mar. 31, 2009, the disclosures of such applications being incorporated herein by reference in their entirety for all purposes.FIELD OF THE INVENTION[0002]The present invention relates to a separation membrane suitable for use in the fields of water treatment, manufacture of pharmaceuticals, food-stuff industry, membrane for blood purification and the like, and a method for producing the same. More particularly, the present invention relates to a separation membrane suitable for the removal of microsubstances such as viruses in a liquid, and a method for producing the same.BACKGROUND OF THE INVENTION[0003]Recently, separation membranes have been utilized in various fields of water treatment, food-st...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): B01D39/00B01D67/00B01D39/14B29C47/00B01D71/34C02F1/44
CPCB01D71/34B01D67/0009B01D2323/06C02F1/444B01D69/1213B01D69/1212B01D69/088B01D69/085B01D67/0016B01D69/10B01D71/441B01D71/401B01D71/14B01D2323/12B01D2325/02833B01D2325/02834B01D2325/0283B01D2325/36
Inventor KOMORI, KENJIISHIZAKI, TOSHIYUKIIWAI, KENTAFU, XUNYAOMINEGISHI, SHINICHIMINAKI, NAO
Owner TORAY IND INC